1. Field of the Invention
The present invention relates to a grommet for protecting a wire group from water, and particularly a wire group of an automotive vehicle where a single wire group is divided into two or more wire bundles. The grommet is designed to protect a wire group from water particularly when the wire group is arranged between a roof and a back door of a hatch-back type automotive vehicle in which a back door window can be opened and closed independently of the opening and closing movement of a back door. Furthermore the present invention relates to a method for arranging such a grommet and an use thereof.
2. Description of the Prior Art
A wire group for supplying power to a back door of a hatch-back type vehicle is used with a prior art grommet 5 as shown in FIG. 6. The prior art grommet 5 includes a narrow tube portion 5a through which the wire group is to be passed and conical large diameter portions 5b, 5c provided at the opposite ends of the narrow tube portion 5a. One large diameter portion 5b of the prior art grommet 5 is mounted in a through hole 2 formed in an end portion of a roof panel 1, and the other large diameter portion 5c thereof is mounted in a through hole 4 formed in a back door frame, as shown in FIGS. 7 and 8. A wire group W is arranged into the inside of a door through the through hole 2 of the roof panel 1, through the narrow tube portion 5a of the grommet 5 and through the through hole 4 of the back door frame 3.
In some hatch-back type vehicles, a back door window mounted on a back door can be opened and closed independently of the opening and closing movement of the entire back door. In such hatch-back type vehicles, a back door frame has a double structure as shown in FIG. 9. The wire group is arranged while being divided and inserted into a through hole 4a formed in a door main frame 3a of the back door and a through hole 4b formed in a door window holding frame 3b.
In this case, as shown in FIG. 10, grommets 10A, 10B, 10C are mounted in the respective through holes 2, 4a, 4b of the roof panel 1, the door main frame 3a and the window holding frame 3b, respectively. However, in a water exposure area (Y) between the roof panel 1 and the frames 3a, 3b of the back door, the wire group W is not covered by the grommet and, accordingly, there is a likelihood that water enters the inside of the roof or back door (inside the frame) by running between the wires of the wire group W. Thus, at the openings of the grommets 10A, 10B and 10C, a water stop material such as a hard resin is filled between the wires of the wire group W to fix the entire wire group. However, it takes a time and a high cost to fill the water stop material. Further, the water exposure area (Y) is visible from the outside and does not look nice because the wire group is exposed.
The present invention was developed in view of the above problems, and an object thereof is to securely prevent a wire group from being exposed to water when being arranged, preferably while being divided into two or more wire bundles in a water exposure area in a vehicle.